Hioki 3256-50 User manual

INSTRUCTION MANUAL
DIGITAL HiTESTER
3256-50
3256-51

i
Introduction ............................................................. 1
Inspection ............................................................... 1
Safety Notes ........................................................... 2
Usage Notes........................................................... 6
Chapter 1 Overview 9
1.1 Product Overview ................................... 9
1.2 Features .................................................. 9
1.3 Parts Names and Functions .................10
Chapter 2 Measurement Procedures 15
2.1 Voltage Measurement........................... 16
2.2 Frequency Measurement...................... 18
2.3 Current Measurement........................... 19
2.4 Resistance Measurement..................... 22
2.5 Continuity Check................................... 23
2.6 Diode Check......................................... 24
Chapter 3 Additional Functions 25
3.1 HOLD AUTO Function .......................... 25
3.2 HOLD Function ..................................... 26
3.3 Overflow Warning Function ..................27
3.4 Relative Display Function ..................... 28
3.5 Auto Power Save Function ................... 30
3.6 Voltage Detecting Function ................... 31
3.7 Dynamic Recording Function ................ 32
3.8 Memory Function .................................. 33
Contents

ii
Chapter 4 Specifications 35
4.1 General Specifications ..........................35
4.2 Accuracy ................................................39
Chapter 5 Maintenace and Service 43
5.1 Replacing the Batteries and Fuses ........43
5.2 Cleaning ................................................45
5.3 Service ..................................................45

1
Thank you for purchasing the HIOKI "3256-50/51
DIGITAL HiTESTER". To obtain maximum perfor-
mance from the product, please read this manual
first, and keep it handy for future reference.
• When you receive the product, inspect it carefully
to ensure that no damage occurred during ship-
ping. In particular, check the accessories, panel
switches, and connectors. If damage is evident, or
if it fails to operate according to the specifications,
contact your dealer or Hioki representative.
• Before using the product the first time, verify that it
operates normally to ensure that the no damage
occurred during storage or shipping. If you find any
damage, contact your dealer or Hioki representa-
tive.
• Before using the product, make sure that the insu-
lation on the test leads is undamaged and that no
bare conductors are improperly exposed. Using
the product under such conditions could result in
electrocution. Replace the test leads and probes
with the specified Hioki Model 9207-10.
Introduction
Inspection

2
Accessories 9207-10 TEST LEAD .................. 1
Instruction Manual....................... 1
R03 Manganese battery.............. 2
(Supplied with this product, for
monitor)
9378 CARRYING CASE*1
(3256-50 only)
Protective holster*2 (3256-51only)
This manual contains information and warnings
essential for safe operation of the product and for
maintaining it in safe operating condition. Before
using the product, be sure to carefully read the fol-
lowing safety notes.
3256-50*1 3256-51*2
Safety Notes
This product is designed to conform to IEC
61010 Safety Standards, and has been thor-
oughly tested for safety prior to shipment.
However, mishandling during use could
result in injury or death, as well as damage to
the product. Be certain that you understand
the instructions and precautions in the man-
ual before use. We disclaim any responsibil-
ity for accidents or injuries not resulting
directly from product defects.

3
Safety Symbols
In the manual, the symbol indicates particu-
larly important information that the user should
read before using the product.
The symbol printed on the product indicates
that the user should refer to a corresponding topic
inthemanual(markedwiththe symbol)before
using the relevant function.
Indicates that dangerous voltage may be present
at this terminal.
Indicates a double-insulated device.
Indicates a grounding terminal.
Indicates DC (Direct Current).
Indicates AC (Alternating Current).
Indicates DC (Direct Current) or AC (Alternating
Current).

4
The following symbols in this manual indicate the
relative importance of cautions and warnings.
Other Symbols
Accuracy We define measurement tolerances in terms of f.s.
(full scale), rdg. (reading) and dgt. (digit) values,
with the following meanings:
Indicates that incorrect operation presents an ex-
treme hazard that could result in serious injury or
death to the user.
Indicates that incorrect operation presents a sig-
nificant hazard that could resultinserious injury or
death to the user.
Indicates that incorrect operation presents a pos-
sibility of injury to the user or damage to the prod-
uct.
Advisory items related to performance or correct
operation of the product.
Indicates the quick guide for operations
Indicates the prohibited action
❖Indicates the reference
f.s. (maximum display value or scale length)
The maximum displayable value or the full length
of the scale. This is usually the maximum value of
the currently selected range.
rdg. (reading or displayed value)
The valuecurrentlybeingmeasured andindicated
on the measuring product.
dgt. (resolution)
The smallest displayable unit on a digital measur-
ing product, i.e., the input value that causes the
digital display to show a "1".

5
Measurement categories (Overvoltage categories)
This product complies with CATIII (600 V), CATII (1000 V) safety
requirements.
To ensure safe operation of measurement products, IEC 61010
establishes safety standards for various electrical environments,
categorized as CAT I to CAT IV, and called measurement cate-
gories. These are defined as follows.
Higher-numbered categories correspond to electrical environ-
ments with greater momentary energy. So a measurement
device designed for CAT III environments can endure greater
momentary energy than a device designed for CAT II.
Using a measurement product in an environment designated
with a higher-numbered category than that for which the product
is rated could result in a severe accident, and must be carefully
avoided.
Never use a CAT I measuring product in CAT II, III, or IV envi-
ronments.
The measurement categories comply with the Overvoltage Cate-
gories of the IEC60664 Standards.
CAT I Secondary electrical circuits connected to an AC elec-
trical outlet through a transformer or similar device.
CAT II Primary electrical circuits in equipment connected to an AC electrical outlet by a power cord (portable tools,
household appliances, etc.)
CAT III Primary electrical circuits of heavy equipment (fixed
installations) connected directly to the distribution
panel, and feeders from the distribution panel to out-
lets.
CAT IV The circuit from the service drop to the service en- trance, and to the power meter and primary overcur-
rent protection device (distribution panel).

6
Follow these precautions to ensure safe operation
and to obtain the full benefits of the various func-
tions.
Usage Notes
• To avoid electric shock, do not allow the
product to get wet, and do not use it when
your hands are wet.
• Do not use the product where it may be
exposed to corrosive or combustible
gases. The product may be damaged or
cause an explosion.

7
Observe the following to avoid damage to the
product.
• Installation and Operating Environment
Between 0°C and 40°C; 80% RH or less;
indoors only. However, it can be safely operated
at as low as -10°C.
• Do not store or use the product where it could
be exposed to direct sunlight, high temperature
or humidity, or condensation. Under such condi-
tions, the product may be damaged and insula-
tion may deteriorate so that it no longer meets
specifications.
• This product is not designed to be entirely
water- or dust-proof. To avoid damage, do not
use it in a wet or dusty environment.
• Do not use the product near a device that gener-
ates a strong electromagnetic field or electro-
static charge, as these may cause erroneous
measurements.
• To avoid damage to the product, protect it from
vibration or shock during transport and handling,
and be especially careful to avoid dropping.
• Adjustments and repairs should be made only
by technically qualified personnel.
• If the protective functions of the product are
damaged, either remove it from service or mark
it clearly so that others do not use it inadvert-
ently.
• To avoid corrosion from battery leakage, remove
the batteries from the product if it is to be stored
for a long time.
Direct
sunlight
High temper
-
ature, high
humidity, du
st
Electromag
-
n
etic radiatio
n
Impact,
dropping

8
• Accurate measurement may be impossible in the
presence of strong magnetic fields, such as near
transformers and high-current conductors, or in
the presence of strong electromagnetic fields
such as near radio transmitters.
• To avoid battery depletion, turn the function
selector OFF after use (the Auto Power Save
feature consumes a small amount of current).
• The indicator appears when battery voltage
becomes low. Replace the batteries as soon as
possible.

9
1.1 Product Overview
This measurement product is a multi-functional
digital multimeter capable of measuring DC and
AC voltages, DC and AC currents, and the resis-
tance, checking the diode and continuity, and
detecting voltage.
Compliance with CE marking requirements
The measurement product is designed to comply
with the international safety standard (IEC61010-
1) and EMC standards.
Safety-designed handy digital multimeter
The measurement product is equipped with test-
lead misinsertion preventive shutters and fast-act-
ing fuses at the current measurement terminals.
Multi-functional and voltage detecting
• Live conductors can be examined safely and easily.
• The Hold Auto function allows measured values to
be maintained by simply disconnecting the test
leads.
• The Hold function maintains the displayed value.
• The Memory function saves the held value dis-
played.
• The Recording function displays the maximum,
minimum, average, and currently measured values
selectively.
• The Relative function displays any discrepancy
from the reference.
Overview Chapter 1
1.1 Product Overview
1.2 Features

1.3 Parts Names and Functions
10
1.3 Parts Names and Functions
V.Ωterminal
Terminalusedto
measure voltag-
es and resis-
tances
(red test lead)
COM terminal
Terminal common to
all functions
(black test lead)
Aterminal
Terminal used to
measurecurrents
in 10-A mode
LCD display *
H.AUTO/REL
Button *
RANGE
Button *
Function
Selector
(Selectsfunctions
and turns the
power on/off)
REC•MEMO
Button
(Pressthisbutton
to change to the
function indicat-
ed in blue.)
For other func-
tions, see the fol-
lowing pages.
μA.mA terminal
Terminal used to
measure currents in
μA/mA mode
*: for details, see
the following
pages
The terminal shutter works together with the
function selector to prevent incorrect operation.
Note that if the function selector is toggled with
the test leads connected, the measurement
product may be damaged.

11
1.3 Parts Names and Functions
LCD(Display)
Indicates HOLD AUTO/
HOLD function
Indicates Relative function
Indicates Autoranging
function
Indicates DC
voltage/cur-
rent function
Indicates AC
voltage/cur-
rent function
Indicates low
battery volt-
age
Lights up when the voltage
drops below the battery
accuracy guarantee voltage
(2.2±0.1 V)
Indicates Recording function
Indicates Continuity Check functio
n
Indicates Diode Check functio
n
Indicates Auto Powe
r
Save is enable
d
Frequency unit
s
Resistance and
continuitychec
k
units
Voltage and di
-
ode check unit
s
Current units
Indicates the
memory data
number
Bar-graph scale (42 dots)
Bar graph (with polarity indicator)
Decimal point
Changes to the func-
tion indicated in blue
Toggles between AC
and DC modes(Cur-
rent measurement)
(page 19)
Recording function
(Displays MAX/MIN/
AVG)*1 (page 32)
Voltage Detecting
(page 31)
Memory Function
(page 33)
Cancels the Auto
Power Save function
*2 (page 30)
Changes the manual
range and selects
range
Changes the auto
range from the manu
-
al range*1
Changes the input
level
(Frequency function)
(page 18
)
Calls data from mem
-
ory*2 (page 34
)
HOLDAUTOfunction
(Holds the measured
value) (page 25)
Turns the HOLD
function on/off *2
(page 26)
Turns the Relative
function (displaying
the relative value) on/
off*1 (page 28)
REC•MEMO H.AUTO/REL RANGE
*1: Press the button for at least 1 second (REC
and REL require the button to be pressed
for a longer time).
*2: Turn on the power while pressing the but-
ton, and hold the button down until a beep
-
ing sound is generated (power-on option).

1.3 Parts Names and Functions
12
Measurements Operations (page)
AC voltage 16
DC voltage 16
DC/AC Current
(40 μA) 20
DC/AC Current
(400/4000 μA) 20
DC/AC Current
(40/400 mA) 21
DC/AC Current
(10A) 21
Resistance 22
Continuity 23
Diode 24
(Diode Check function)
Continuity function
Resistance function
DC voltage function
(Voltage detecting)
(Frequency
function)
AC voltage
function
Power OFF
40μA DC/AC current
function
μA DC/AC current
function
mA DC/ACcurren
t
function
10A DC/AC
current function
Function Selector
Press REC•MEMO when the
function in parentheses is being
used.
Quick Reference
Indicates the function selector position
Indicates the terminal to which the red
test lead should be connected
Indicates the terminal to which the
black test lead should be connected
Switches betwee
n
measurement to
display in paren-
theses.
V
REC•MEMO
( )
Example
VMeasuremen
t
VMeasureme
nt
40 μ A
( )
REC • MEMO
Measuremen
t
μ A
( )
REC • MEMO
Measuremen
t
mA
( )
REC • MEMO
Measureme
nt
10A
( )
REC • MEMO
Measureme
nt
ΩMeasureme
nt
(
)
REC • MEMO
Measureme
nt
( )
REC • MEMO
Measureme
nt

13
1.3 Parts Names and Functions
Frequency 18
Voltage
detecting 31
V
REC • MEMO
RANGE
( 1 - 4 )
"Hz" lights up
Measur
e-
ment
V
Bring test leads
c
losetothepowe
r
line.
REC • MEMO × 2
"1" lights up
RANGE
( 1 - 4 )
Hold the measured value. (HOLD AUTO function)
This function is used whenthe displayed value cannot be checked during
measurement (such as when necessary to measure the conductor in a
dark place or using both hands.
25
Hold the measured value. (HOLD function)
26
"O.F" is displayed to provide a warning
(Overflow Warning function)
When the measured value exceeds the maxi-
mum value, "O.F" is displayed. 27
Use this function to check any discrepancy from the reference,
or to control the resistance for the purpose of zero adjustment
(Relative function)
Cancellation: H.AUTO / REL (press again)
28
Quick Reference (application)
: Turn on the power while pressing
the button (hold the button down
until a beeping sound is generated
).
:Button
REC•MEMO REC•MEMO
<1 second:
Press the button for at least 1 second.
Example
V/ V/Ω/
4
0μA/μA/mA/
10A
H.AUTO/REL
"HOLD"
Blinking (Intermittent
sound)
Movethetestleadsawayfrom
the measurement object.
V/ V/Hz/
Ω
/
//40μA/
μ
A/mA/10A
H.AUTO/REL H.AUTO/RE
L
Measure-
ment
V/ V/40μA
/
μ
A/mA/10A
V/ V/Ω/
4
0μA/μA/mA/
1
0A
H.AUTO/REL
D
isplaythe
r
eference. (<1 second) ("REL"
lights up)

1.3 Parts Names and Functions
14
Cancel the Auto-Power Save function.
(Auto-Power Save function)
Enable the Power Save function: 30
Check the maximum, minimum, and average values during
measurement. (Recording function)
MAX:maximum value/ MIN:minimum value/
AVG:average value/ MAX MIN AVG: Current
value
Cancellation: REC•MEMO (press again)
32
Save the measured value to memory. (Memory function)
33
Call the saved data.
34
Delete all data from memory.
34
V/ V/Hz/
V
D/Ω///
4
0μA/μA/mA/
10A
REC•MEMO
Press this button until a
beeping sound is generated
.
OFF Function
change
("APS"
lights up)
Power
Save
mode
After
10 minutes
V/ V/Ω/
4
0μA/μA/mA/
1
0A
R
EC•MEMO
(
<1 second)
H.AUTO/RE
L
( MAX MIN AVG
)
(" MAX MIN AVG"
lights up )
V/ V/Ω/
4
0μA/μA/mA/
1
0A
Hold the dis-
played value ("MEM."
lights up
)
REC•MEMO
H.AUTO/REL
V/ V/Ω/
4
0μA/μA/mA/
1
0A
Memory-data
display
Select MEM#
.
RANGE RANG
E
V
V/ V/Ω/
4
0μA/μA/mA/
10A
RANGE
REC•MEMO
RANGE
(<1 second)
V

15
1.3 Parts Names and Functions
Measurement
Procedures Chapter 2
Observe the following precautions to avoid
electric shock.
• Always verify the appropriate setting of the
function selector before connecting the
test leads.
• Disconnect the test leads from the mea-
surement object before switching the func-
tion selector.
• When it is necessary to replace the mea-
surement terminal, remove the test lead
from the measurement object and discon-
nect the lead from the terminal before tog-
gling the function selector.
Even when the shutter is closed, the termi-
nals are not sufficiently separated. To avoid
electrocution, do not touch the terminals.
When the shutter is damaged, discontinue mea-
surement and repair it.

2.1 Voltage Measurement
16
2.1 Voltage Measurement
• The maximum input voltage is 1000 VDC,
1000 Vrms, or 107V•Hz.
However, for CATIII circuits, the maximum
voltage is 600 Vrms. Attempting to mea-
sure voltage in excess of the maximum
input could destroy the product and result
in personal injury or death.
• To avoid electrical shock, be careful to
avoid shorting live lines with the test leads.
• For safety, test lead connections must
always be made at the secondary side of a
circuit breaker.
• The maximum rated voltage between input
terminals and ground is 1000 V DC/AC
(CATII), 600 V DC/AC(CATIII), or 107V•Hz.
Attempting to measure voltages exceeding
this limit with respect to ground could dam-
age the product and result in personal
injury.
DC Voltage
Measurement 1. Move the functio
n
selector to the
V
position for AC mode o
r
to the Vposition fo
r
DC mode (in eithe
r
case, “V” lights up).
2. Connect the red tes
t
lead to terminal V.Ω
,
and the black test lea
d
to terminal COM.
AC Voltage
Measurement
Black
Red